Field of the Invention
The present invention relates to an image formation apparatus including a fixing device which fixes a toner image on a sheet.
Description of the Related Art
In recent years, there is a demand for electrophotographic image formation apparatuses to satisfactorily form images on a variety of storage media. In particular, it is difficult to satisfactorily form an image on embossed paper, and there is a demand for better fixing a toner image to embossed paper.
It is difficult to bring a fixing belt into contact with toner in a recess of embossed paper, and it is difficult to transfer sufficient heat from the fixing belt to the toner in the recess. This results in a toner image poorly fixed to the embossed paper.
An image formation apparatus which can suppress poor fixing of a toner image to embossed paper is disclosed for example in Japanese Laid-Open Patent Publication No. 2015-172613.
The image formation apparatus disclosed in Japanese Laid-Open Patent Publication No. 2015-172613 includes: a tension modifying means that positionally changes a plurality of support rollers on which a fixing belt is wound to modify a tension exerted to the fixing belt; and a unit positionally changing a tension member, that positionally changes the tension member disposed on the side of an inner circumference of the fixing belt upstream of a nip portion to modify a contact area of a pressure applying roller disposed inside the fixing belt and the fixing belt.
In fixing an image on embossed paper, the nip portion has a nip width increased by decreasing a tension exerted to the fixing belt or changing the tension member's position. This helps to bring the fixing belt into contact with the toner in the recess to allow sufficient heat to be transferred to the toner in the recess from the fixing belt. As a result, satisfactory fixing to embossed paper can be obtained.